How is the "MATCHING_INFO" field constructed?

Hello to all,

I'm looking to know how the "MATCHING_INFO" field is constructed in the "GEN_LED_VOUCHER_ROW_TAB" table.
I looked in many packages but I found absolutely nothing..

The value of the field always begins with :
INVOICE^…, or by “PUR ORDER^...”

I would like to know why this field is built this way.
Do you have a lead for me?
Thanks in advance !